Numerical modelling of integrated hydrogeological systems in complex porous and fractured media

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Canada has some of the world's most abundant groundwater resources which are critical for drinking water, agricultural and industrial use, and for maintaining ecosystems and stream flow. These resources are being threatened by over-exploitation, contamination and climate change. Some of the most complex groundwater systems are found within fractured porous media which are challenging to characterize, remediate, and protect. This Discovery Grant Proposal "Numerical modelling of integrated hydrogeological systems in complex porous and fractured media" outlines a research plan for developing and applying new computational modelling approaches to test conceptual models, to better protect and manage groundwater resources, and to improve our ability to remediate contaminated sites and prevent future impacts. The proposal has been developed in part within the context of the Researcher's Tier II Canada Research Chair in Quantitative Hydrogeology of Fractured Porous Media.The proposal contains three primary research themes involving numerical modelling of fractured systems: 1. Development of numerical methods for protecting groundwater resources in fractured rock aquifers,2. Applying numerical models to optimize remediation of contaminated fractured aquifers, and3. Understanding the risks from fractured hydrogeological systems under stressed conditions.Developing quantitative numerical tools for ensuring sustainable use of limited groundwater resources is the underlying objective encompassing all themes.Theme 1 of the proposal will focus on developing new numerical tools and modelling approaches for protecting groundwater in fractured rock aquifers which are becoming more commonly used for urban and rural water supply. New computational techniques for identifying source water provenance for municipal water supply wells in fractured rock, and for predicting groundwater age and life expectancy as a measure of aquifer and well vulnerability, respectively, will be fully developed for discretely-fractured porous media in three dimensions.In aquifers which are already contaminated, more efficient and cost-effective remediation methods are needed. Under Theme 2, a robust 3D numerical flow and transport model will be developed for simulating 'treatment-train' persulfate-ISCO (in-situ chemical oxidation) remediation of groundwater contaminated by petroleum hydrocarbons. The approach includes sulfate-enhanced in-situ bioremediation (IBR), coupled to reactions with the natural background geochemistry. The model will be developed for both porous and discretely-fractured porous media, and will be tested at monitored field sites under various hydrogeologic conditions. Optimal design parameters (including injection concentrations, flow rates, and treatment sequence timing), uncertainty, and effects of heterogeneity and background geochemistry will be investigated.Theme 3 addresses environmental impacts of shale gas development on groundwater resources, focusing on simulating potential disturbances to deep regional flow systems in fractured rock caused by hydraulic fracturing, and assessing the leakage risks of methane gas and formation brines into shallow freshwater aquifers. These environments challenge current models and require innovative numerical strategies to fully understand. The simulation results will be used to help design groundwater monitoring strategies for early detection of impacts on drinking water resources.The proposal will lead to direct HQP training of 2 MSc and 2 PhD students.